SECTION YI 

 THE DIGESTIVE SYSTEM 



THE digestive system includes the alimentary canal and various 

 organs connected with it. The greater part of the digestive 

 system lies within the abdomen. The alimentary canal consists 

 of the following parts : Mouth, pharynx, oesophagus, stomach, 

 duodenum, small intestine (jejunum, ileum), large intestine, 

 rectum ; and the organs connected with it are salivary glands, 

 liver, pancreas. The whole of the alimentary canal consists of 

 structures formed of one or more muscular coats lined with 

 mucous membrane. 



The Mouth is the first division of the alimentary canal, and 

 contains the parts necessary for mastication and the openings 

 of the ducts of the salivary glands. The food passes from the 

 mouth into the pharynx, a large space at the back of the nose 

 and mouth, containing in its lower half the greater part of the 

 tongue and the larynx. The pharynx ends at the level of the 

 sixth cervical vertebra, and from it pass the larynx and trachea 

 in front and the oesophagus behind. 



The (Esophagus is the part of the digestive canal which leads 

 from the pharynx to the stomach. It is a muscular tube, flat- 

 tened by the trachea and the other structures lying on it. It lies 

 in the thorax and extends from the sixth cervical vertebra to 

 the eleventh dorsal vertebra, where it passes through the dia- 

 phragm and enters the stomach. It is closely applied to the 

 vertebral column, lying behind the other structures in the 

 thorax. 



The Abdominal Cavity, which contains the rest of the 

 alimentary canal, is bounded above by the diaphragm, below 

 by the pelvic floor, posteriorly by the lumbar vertebras, and 



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